MADISON (WKOW) -- Sheriff's deputies have searched the home of a Madison-area man suspected of participating in a crime related to the Republican National Convention in Minnesota.

Investigators in Ramsey County, Minnesota, believe 22-year-old David Clerkin of the Town of Blooming Grove man is one of two men who threw a pair of 50-pound sandbags off a freeway overpass in St. Paul on Sept. 1.

One sandbag landed on a bus taking delegates to the convention.

No one was hurt, although authorities said one passenger described the impact as causing chaos.

The other man has been charged with assault in the second degree and making terroristic threats.

Clerkin has not been charged with a crime, and his father, Bill Clerkin told 27 News authorities are distorting his son's actions in Minnesota.

"He was simply there as a protester and when protesters start being described as terrorists, I think's that a problem."

Court documents show authorities believe clothes and shoes worn by one man involved in the incident, and a mole on the arm of that man match up with Clerkin. But documents also show no clothes, nor anything else sought by investigators, were found during the search of the Clerkin home. "They've got the wrong person," Bill Clerkin told 27 News.

David Clerkin, nor the head of the investigation, Ramsey County Sheriff Bob Fletcher have returned calls from 27 News.

Authorities also alleged Clerkin was connected to what investigators called an anarchist group. Bill Clerkin conceded David Clerkin has ties to the group, but disputed the anarchist label.